1. Field of the Invention
The invention relates to a novel resilient foot insert for an artificial foot, having at least one spring element for determining the spring rigidity of the artificial foot, and an adapting device for changing the spring rigidity of the spring element.
2. Description of Related Art
One embodiment of a foot insert described in DE-A 42 05 900 comprises three leaf springs. A leaf spring with shallow bends is arranged in the heel region and, by way of its front end, is connected to a bent forefoot spring in the forefoot region. One end of the bent forefoot spring extends upwardly into the foot-connection region and is screwed to an adapter. The other spring end projects into the front region of the foot. The forefoot spring is assigned a second, somewhat shorter leaf spring. The top end of the shorter leaf spring is screwed to the top end of the forefoot spring in the region of the adapter connection.
The area in which the shorter leaf spring joins the forefoot spring defines a receiving space which increases in size in a wedge-like manner toward the front. An air-filled pressure pad is supported by the forefoot spring and the shorter leaf spring in the receiving space. The patient can change the resiliency characteristics of this foot insert by changing the air pressure in the pressure pad. The pressure pad can be manually inflated with the aid of a hand pump. A valve device allows the interior pressure of the pressure pad to be reduced.
The walking dynamics of the patient are a function of the patient""s form on a specific day and also of the activity which the patient is carrying out. It is quite conceivable for adaptation to the patient""s form on a specific day to be carried out by a gradually adapting system (with the aid of an air-filled pad, as described above). On the other hand, adapting to a patient""s activity at any one moment in time (e.g., at the workplace) may have to be done very quickly and, sometime, may need to be done from one step to the next. The presently known pneumatic systems are not quite capable of adapting as quickly as necessary.
The difficulties suggested in the preceding are not intended to be exhaustive, but are among many tending to reduce the effectiveness of the foot insert. Other noteworthy problems may exist; however, those presented above should be sufficient to demonstrate that such methods and apparatuses appearing in the past will admit to worthwhile improvements.
Accordingly, it is a general object of the invention to provide a foot insert for an artificial foot that will obviate or minimize the disadvantages of the type previously described.
It is a specific object of the invention to provide a foot insert for an artificial foot having increased wearing comfort.
It is another object of the invention to provide a foot insert for an artificial foot that adapts quickly to changes in the patient""s activity.
A preferred embodiment of the invention, which is intended to accomplish at least some of the foregoing objects, includes at least one spring element for determining spring rigidity of the artificial foot; and an adapting device kinematically connected to the at least one spring element for changing a spring rigidity of the artificial foot, wherein the adapting device is actuated dependent on a load placed on the artificial foot.
Additional objects, features, and advantages of the invention will be set forth in the following description, and, in part, will be obvious from the description, or may be learned by practicing the invention. The objects and advantages of the invention may be realized and obtained by the instrumentalities and combinations particularly pointed out in the appended claims.